Nanoparticles for the delivery of therapeutic agents have the potential to circumvent many challenges associated with traditional delivery approaches including lack of patient compliance to prescribed therapy, adverse effects, and inferior clinical efficacy due to lack of targeted delivery. Important technological advantages of nanoparticles for drug delivery include the ability to deliver water-insoluble and unstable drugs, incorporation of both hydrophobic and hydrophilic therapeutic agents, and ability to utilize various routes of administration. Nanoparticle delivery systems may also facilitate targeted drug delivery and controlled release applications, enhance drug bioavailability at the site of action, reduce dosing frequency, and minimize side effects.
Because of these possible advantages, nanoparticulate systems have been examined for use as drug delivery vehicles, including polymeric micelles, polymers, liposomes, low-density lipoproteins, dendrimers, hydrophilic drug-polymer complexes, and ceramic nanoparticles. Typical polymeric materials utilized in polymeric particulate drug delivery systems include polylactic acid (PLA), poly(D,L-glycolide) (PLG), and poly(lactide-co-glycolide) (PLGA). PLA and PLGA are listed as Generally Recognized as Safe (GRAS) under Sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act, and are approved for use in commercially available microparticulate systems, including Decapeptyl®, Parlodel LA®, and Enantone Depot®, as well as in implant devices, such as Zoladex®.
However, certain nanoparticle systems, such as liposomes, are not amenable for use with certain therapeutic agents. Polymeric nanoparticles developed to date have limited effectiveness, in part because such nanoparticles clear from the body quickly once administered and/or may accumulate in healthy tissue where treatment is not needed. Control of delivery of an active agent, using nanosystems, remains a challenge.
Therefore there is a need for biocompatible compositions capable of extended delivery of active agents, e.g., anti-neoplastic agents, that provide for prolonged and/or increased plasma drug concentrations in a patient, especially as compared to administration of an active agent alone.